The research proposed has as its key objective an understanding of the steps involved in the processing of nuclear RNA in eukaryotic cancer cells. Studies are directed towards understanding the biologic role of nuclear and nucleolar proteins involved in this process. The nuclear ribonucleoprotein particles found both in nucleoli and nucleoplasm are transient structures assembled between rapidly turning over RNA, and some stable proteins. The role of phosphorylation of some stable nuclear proteins, and of protein kinase involved in phosphorylation, will also be studied.